Self-luminous light source for liquid crystal watch (液晶時計用自發光光源)

摘要

A fluorescent body layer has an optic reflection property, contains a radioactive element; Promethium. A spontaneous light for a liquid crystal watch has a reflection layer to reflect or scatter fluorescence. The case shields a x-ray due to a -ray generated in Promethium. The first cover absorbs the -ray, transmits the light coming from the fluorescent body layer. The second cover shields the x-ray due to the -ray.